1. Field of the Invention
The present invention relates to a thermoplastic polymer composition comprising an ethylene-vinyl alcohol copolymer and a crosslinked modified block copolymer, a formed article comprising the polymer composition, and applications of the polymer composition. The thermoplastic polymer composition of the present invention is useful, for example, as sheets, films, packaging materials for beverage and foodstuffs, containers, and packings for containers since it is excellent in both barrier properties to gases, organic liquids and the like and flexibility.
2. Description of the Related Art
Ethylene-vinyl alcohol copolymer has high barrier properties to gases, organic liquids and the like, and does not generate harmful gases during their incineration as polyvinyliden chloride or polyvinyl chloride does. Therefore, it is used for various applications such as packaging materials for foodstuffs. However, since ethylene-vinyl alcohol copolymer is poor in flexibility, it is known that it is used in the form of composition with soft resins such as polyolefin (see Japanese Patent Laid-Open No. 04-164947), or laminates.
Ethylene-vinyl alcohol copolymer usually exhibits a poor affinity and a poor compatibility with other resins. Therefore, it usually is not possible for composition obtained by blending a soft resin to an ethylene-vinyl alcohol copolymer to have a sufficient flexibility and sufficient barrier properties simultaneously. In addition, a laminate including a layer of an ethylene-vinyl alcohol copolymer and a layer of a soft resin has an improved flexibility in comparison with a layer of the ethylene-vinyl alcohol itself, but the flexibility of the laminate may still be insufficient for some applications.